This invention relates to a novel cleaner having bacteria-proof, fungi-proof and algae-proof effects which is to be added to a reaction thermostat using water as medium in scientific apparatus, particularly a thermostatic water bath in an automatic analyzer.
Generally, in the field of the clinical chemistry, measurement of physiologically active substances in such organism samples as serum, urine or tissue fluid, e.g., enzymes, lipids, proteins, etc., is made widely for the purpose of diagnosis of diseases and grasping disease conditions.
Automatic analyzers have various features such as quick operation, high efficiency, high accuracy, convenient handling, small amounts of samples and reagent required for analysis and capability of saving energy, so that they are employed widely in the field .noted above. The measurement is usually done in the order of taking a sample, adding a reagent, mixing, incubation, color comparison (measurement of absorbance) and calculation. The incubation is effected by an air bath system or a water or oil bath system, but most generally a water bath is used as thermostat. The reaction temperature is usually below 50.degree. C. and most generally 37.degree. C. The absorbance is measured by a system, in which measurement is done by sucking up reaction solution from a reaction vessel to a cell, or a system, in which the reaction vessel is measured directly as measurement cell. At present, the latter system is mainly adopted. In the measurement of this system, with a thermostatic water bath as thermostat, light from a light source disposed outside the water bath is passed through the water bath and through a reaction vessel therein to be detected by a sensor disposed on the opposite side of the water bath. In this way, the reaction vessel is also used as cell for measuring. The wavelength used for measurement is usually 340 to 900 nm.
Usually, water in the thermostatic water bath in the automatic analyzer is replaced once or several times a day. At the time of water replacement, air bubbles are frequently attached to the outer wall of the reaction vessel. To prevent this, a slight amount of cleaner is usually added. The cleaner used to this end is usually prepared from various surface active agents as the main component by adding a chelating agent, a pH controller, a preservative agent, etc. to the main component. It has poor bubble-formation property, and it is added to a concentration of 0.05 to 2.0 V/V % in the water bath. However, in the water bath using such water, the component of cleaner serves as source of nutrition to promote generation of algae and growth of various microorganisms (bacteria etc.). Any preservative agent added can not substantially provide any effect. As a consequence, a great error in the measurement of the absorbance was produced by a cause such as generation of algae on the reaction vessel and/or growth of various microorganisms in water in the water bath, etc. For this reason, as the analyzer requires sufficient daily maintenance control, in the use of the apparatus a great deal of labor is required for accuracy maintenance and maintenance control by frequently monitoring or periodically cleaning the inside of the water bath. Therefore, improvement in this respect is strongly desired.